1. Field of the Invention
The present invention relates to a transmitting apparatus for transmitting (including recordal and reproduction) a color video signal in the form of component signals which are a luminance signal Y and two color difference signals P.sub.b and P.sub.r.
2. Description of the Prior Art
In the so-called high vision system, a color video signal is divided into a luminance signal and color difference signals by the following equations (1) and transmitted as component video signals. EQU Y=0.701G+0.87B+0.212R EQU P.sub.b =-0.384G+0.500B+0.116R EQU P.sub.r =-0.445G-0.055B+0.500R (1)
An FM carrier is frequency modulated by the above Y signal and P.sub.b and P.sub.r, signals and the resultant frequency modulated wave (FM wave) is transmitted. In such a transmitting process, various noises are mixed with the FM wave and corresponding noises appear in demodulated Y and P.sub.b and P.sub.r signals after the transmission, which causes deterioration of the resultant color image.
For instance, a case where the above FM signals are recorded onto an optical disk and reproduced will now be considered.
In the above recordal and reproduction, noises which are mixed with a read signal which is derived from an optical disk are so called random noises and there are the following kinds of noises.
(a) Noises in a head amplifier to amplify an RF signal; PA0 (b) So-called disk noises included in an optical disk; and PA0 (c) Optical noises contained in a laser beam used as a reading light beam.
FIG. 1 shows situations of color bar distributions with respect to the Y, P.sub.b, and P.sub.r signals. In the color bar distribution diagram, hatched portions indicate noise components which appear in the transmitting system.
A state in which color noises in a color image are seen has been examined, so that the following points have been found out. That is, on the screen, the color noises are conspicuous in a portion where the luminance is slightly dark and the absolute values of the color difference signals are large (color saturations are high).
The color bars are observed in consideration of the above state in which the color noises on the screen due to the noise signal are seen. A consideration will be first made with respect to the P.sub.b signal. Since the absolute value levels are high in the portions of magenta and blue and the Y level decreases, the color noises are conspicuous in those portions. When observing with regard to the P.sub.r signal, the absolute value levels are high in the magenta and red portions and the color noises are conspicuous in those portions because of the reason similar to that in the case of the P.sub.b signal.